IMEC team shows wireless 'thought-to-text' cap

LONDON  A team of researchers from IMEC, the Holst Center and the lab of neuro- and psychophysiology at the Katholieke Universiteit Leuven has presented Mind Speller, a thought-to-text device intended to help people with motor disabilities.

A number of research institutes are working on similar devices which make use of electro-encephalogram (EEG) brainwaves and positive biological feedback so that individuals can use thought processes alone to control a cursor or a computer action.

The Mind Speller comes in the form of a cap, which IMEC claimed is easy-to-wear and portable. The textual and verbal communications prototype device was presented at Medtech Conference in Stuttgart, Germany, and it is claimed that it could enable people suffering from paralysis or speech or language disorders to communicate.

The Mind Speller captures EEG traces and interprets the brain waves to spell words and phrases. Specifically it detects and interprets what are known as P300 event-related potentials in the EEG-signals of a person that is selecting characters from a display presenting alternate rows and columns of characters. P300 potentials are often used as metrics of cognitive function in decision making processes. However, currently available P300 devices are large, expensive and uncomfortable in use.

The Mind Speller, on the other hand, uses a portable device, the size of a matchbox, connected to a cap that contains electrodes located at specific positions on the head to capture the relevant EEG-signals. The electronics in the matchbox are developed by IMEC and the Holst Center. It contains IMEC's and Holst Center's proprietary eight-channel EEG-chip to process the EEG signals, a commercially available microcontroller that digitizes the EEG signals and a 2.4-GHz radio that transmits the EEG signals wirelessly to a nearby PC. The data is interpreted on the PC by signal processing algorithms developed by the team of Professor Marc Van Hulle at the lab of
neuro- and psychophysiology of the Katholieke Universiteit Leuven.

"The Mind Speller is a generic device that can be easily adjusted to different users. Therefore, it could be a cost-efficient communication solution for people with temporal impairments for whom the existing solutions are too expensive. Moreover, the Mind Speller may help those patients that are not helped with the existing devices driven by motor activity, as the Mind Speller is based on a different principle, using P300 EEG potentials to read people's thoughts," said Professor Van Hulle.

IMEC is adapting the electronics to allow it to work with dry electrodes, thus making the system less difficult to use.